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A208253 Number of n X 3 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors. 1
5, 96, 2040, 43344, 920928, 19566912, 415737216, 8833148160, 187677464064, 3987573838848, 84723785029632, 1800122089230336, 38247105402593280, 812634365429366784, 17266002353004576768, 366849901919230820352 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A208258.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 22*a(n-1) - 16*a(n-2) for n>3.

Conjectures from Colin Barker, Jun 29 2018: (Start)

G.f.: x*(1 - 2*x)*(5 - 4*x) / (1 - 22*x + 16*x^2).

a(n) = (1/32)*sqrt(3/35)*((11-sqrt(105))^n*(-13+sqrt(105)) + (11+sqrt(105))^n*(13+sqrt(105))) for n>1.

(End)

EXAMPLE

Some solutions for n=4:

..0..0..1....0..0..0....0..1..0....0..0..1....0..0..0....0..1..2....0..0..1

..2..0..0....0..1..2....0..1..1....2..0..2....1..2..1....1..2..0....1..1..2

..2..0..1....2..0..0....1..0..2....0..2..0....0..2..2....0..1..0....1..0..1

..2..2..2....1..0..1....1..2..0....2..0..2....0..0..2....2..0..1....2..1..2

CROSSREFS

Cf. A208258.

Sequence in context: A266245 A194616 A285367 * A284664 A194609 A139950

Adjacent sequences:  A208250 A208251 A208252 * A208254 A208255 A208256

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 24 2012

STATUS

approved

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Last modified August 15 09:19 EDT 2022. Contains 356135 sequences. (Running on oeis4.)